feat(core): send address prefix to mailbox API

[zmezei]

Proposed Changes

In Agentverse we want to show the address prefix ("agent" in case of mainnet agent, "test-agent" in case of testnet agent) prepended to the address everywhere where agents are listed/shown (for example agant://agent1qgd5jllcnav0u5dylemttag2cnmdewlpyhsjvy9z03kdr7xwyycyucfjf69 instead of agent1qgd5jllcnav0u5dylemttag2cnmdewlpyhsjvy9z03kdr7xwyycyucfjf69). For this the prefix needs to be sent to the mailbox API when a mailbox agent is created. This PR makes it possible to send the prefix.

Linked Issues

[if applicable, add links to issues resolved by this PR]

Types of changes

What type of change does this pull request make (put an x in the boxes that apply)?

• Bug fix (non-breaking change that fixes an issue).
• New feature added (non-breaking change that adds functionality).
• Breaking change (fix or feature that would cause existing functionality to stop working as expected).
• Documentation update.
• Something else (e.g., tests, scripts, example, deployment, infrastructure).

Checklist

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• I have read the CONTRIBUTING guide
• Checks and tests pass locally

If applicable

• I have added tests that prove my fix is effective or that my feature works
• I have added/updated the documentation (executed the script in python/scripts/generate_api_docs.py)

Further comments

[if this is a relatively large or complex change, kick off a discussion by explaining why you chose the solution you did, what alternatives you considered, etc...]

[jrriehl]

LGTM